What’s Vulnerable › Vulnerabilities
CVE-2017-18509
- Severity: high (CVSS 7.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.8% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2019-08-13 · updated 2026-06-17
- Weakness: CWE-20
Description
An issue was discovered in net/ipv6/ip6mr.c in the Linux kernel before 4.11. By setting a specific socket option, an attacker can control a pointer in kernel land and cause an inet_csk_listen_stop general protection fault, or potentially execute arbitrary code under certain circumstances. The issue can be triggered as root (e.g., inside a default LXC container or with the CAP_NET_ADMIN capability) or after namespace unsharing. This occurs because sk_type and protocol are not checked in the appropriate part of the ip6_mroute_* functions. NOTE: this affects Linux distributions that use 4.9.x longterm kernels before 4.9.187.
Affected products
- Canonical Ubuntu Linux: 16.04
- Debian Linux: 8.0, 9.0, 10.0
- Linux kernel: before 3.16.72; from 3.17 before 4.4.187; from 4.5 before 4.9.187; from 4.10 before 4.11 — fixed in 3.16.72, 4.11, 4.4.187, 4.9.187
How to fix
Upgrade to a fixed version: Linux kernel 3.16.72, 4.11, 4.4.187, 4.9.187. Check the vendor advisory for mitigations.
References
- http://packetstormsecurity.com/files/154059/Slackware-Security-Advisory-Slackware-14.2-kernel-Updates.html
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=99253eb750fda6a644d5188fb26c43bad8d5a745
- https://github.com/torvalds/linux/commit/99253eb750fda6a644d5188fb26c43bad8d5a745
- https://lists.debian.org/debian-lts-announce/2019/08/msg00016.html
- https://lists.debian.org/debian-lts-announce/2019/08/msg00017.html
- https://lists.openwall.net/netdev/2017/12/04/40
- https://pulsesecurity.co.nz/advisories/linux-kernel-4.9-inetcsklistenstop-gpf
- https://salsa.debian.org/kernel-team/linux/commit/baefcdc2f29923e7325ce4e1a72c3ff0a9800f32
- https://seclists.org/bugtraq/2019/Aug/26
- https://support.f5.com/csp/article/K41582535
- https://support.f5.com/csp/article/K41582535?utm_source=f5support&%3Butm_medium=RSS
- https://usn.ubuntu.com/4145-1/
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